Ordinarily I'd just let it go, but this wasn't the first time things have gone wrong at that particular store. My boss had to wait over an hour for her lunch that same week, for example. So, I did what I do best: I wrote an angry letter directly to the CEO. (I write angry letters for a living, lol.)
Apparently my poison-pen bitchbomb must have been delivered today, because my phone has absolutely EXPLODED with various apologetic people from the franchise's headquarters scrambling & trying to contact me. Good enough; I don't really want a refund or a free meal or anything. I just wanted to make sure the upper echelon of management was aware of the fucktardery going on at one of their franchises, and how it's affecting their business. Judging by the results, I got my point across.
The bottom line is that good effective letters of complaint can often get quite a bit accomplished. :D
I am hoping other bad_service members will share their tips on writing complaint letters, so that this won't be a total FAILPOST and people can actually learn some useful info. Knowing how to bitch properly (and at the right people!) can really come in handy when a company screws you over.
EDITED TO ADD: I scanned a copy of the letter I sent (edited to remove contact/personal info). click here (apologies for the crappy scan, my scanner is FILTHY haha)